Machines used to shape workpieces generally include a driving motor, a driven rotatable shaft on which a workpiece may be removably mounted, and retaining devices attachable to the shaft for demountably holding the workpiece. More particularly, the new and useful refinishing tool disclosed and claimed in this document is useful for refinishing a vehicular brake or flywheel mountable on a shaft or arbor of a brake lathe for refinishing operations on a vehicular brake (collectively, “brake”).
One such workpiece is a motor vehicle brake, either a drum or disk (collectively, “brake”). Brakes become worn during use on vehicles. Worn brakes, however, may be machined, refinished, balanced, and resurfaced for subsequent re-use. Tools are available to reciprocally engage and shape surfaces of brake drums for re-use. Refinishing work has become increasingly difficult, however, because the size of brakes has diminished in recent years.
A brake, of course, is any mechanical device for arresting the motion of a wheel (and accordingly the vehicle) by means of friction. Kinetic energy is converted into heat energy through use of frictional forces applied to the wheels of the vehicle, causing the vehicle to slow or stop. A drum brake is a type of brake using a drum-shaped metal cylinder attached to the inner surface of the wheel of a motor vehicle and rotating within it. When the brake is applied, curved brake shoes with friction linings press against the drum's inner circumference to slow or stop the vehicle. The rotating part of a disc brake is also called a “rotor.” The non-rotating, basically stationary, component of a disc brake system is a brake caliper that applies force from a hydraulic system to the rotor or disc to decelerate or stop a vehicle.
Brake fade is a condition brought about by repeated or protracted braking that results in reduced braking effectiveness (“fading”). Heat is the primary cause of fading, which in turn causes expansion and other undesirable thermal effects on a brake. Although disc brakes are less prone to fade because rotors are more effectively cooled by air moving across the brakes, and can be internally vented to increase resistance to fade, nevertheless persistent stop-and-start braking causes damage to any brake, whether a drum or rotor. Accordingly, a significant industry has developed in connection with the machining, refinishing, balancing and resurfacing of brake drums and rotors (collectively, “refinishing”).
To refinish a brake, a drum or a rotor is mounted on a rotatable shaft or arbor of a brake lathe system. During operation, forces due to rotation and gravity tend to preclude uniform rotation of the rotating arbor on which a brake has been mounted. The arbor and devices mounted on the arbor for refinishing do not rotate in a single, unvarying plane of rotation. The forces acting on a rotating arbor and brake may distort in one or more planes and along one or more axes of rotation. The forces exert a variety of angular and planar forces that affect how accurately and quickly the brake lathe operator may work on a brake to refinish it.
In addition, forces and force vectors may induce harmonics and vibrations that may be transmitted to the arbor, brake and other components of the lathe. A non-uniform rotation of a brake during a refinishing operation may cause a cutting or refinishing tool brought into contact with a brake surface to produce an inferior surface.
To overcome such undesirable problems, the inventor named in this document has received a number of U.S. patents for apparatus and methods that resolve in exemplary fashion adverse consequences of such forces, thus improving the refinishing process, including U.S. Pat. No. 6,279,919B1 issued Aug. 28, 2001 for an Apparatus for Securing a Workpiece to a Rotatable Machine Member; U.S. Pat. No. 6,554,291B1 issued Apr. 29, 2003 for an Apparatus for Securing a Workpiece to a Rotatable Machine Member; U.S. Pat. No. 6,397,989B1 issued on Jun. 4, 2002 for an Apparatus for Reducing Harmonics and Vibrations of a Rotatable Base Piece; U.S. Pat. No. 6,631,660B1 issued Oct. 14, 2003, for a Self-Aligning Arbor Nut System. The inventor currently has pending a U.S. patent application for a Refinishing tool Ser. No. 10/684,021 filed on Oct. 10, 2003 (“Pending Application”), as well as application Ser. No. 11/365,733 for a Reversible Flange Plate filed on Mar. 1, 2006, and, as indicated above, application Ser. No. 11/376,271, entitled, Adapter Assembly for Hubbed Rotor filed on Mar. 15, 2006. The patents and application are collectively referred to in this document as the “Prior Patents and Applications” for ease of reference.
The apparatus disclosed and claimed in the Prior Patents and Applications have proven useful in a variety of situations and installations, and uniquely adapted for uses described in the Prior Patents and Applications. The apparatus disclosed and claimed in this document, however, is directed to refinishing a brake.
Tools available for refinishing a workpiece such as a brake include boring bars. Conventional boring bars include a unitary monolithically formed bar with a cutting or refinishing device (collectively, “cutter”) attached to one end of the unitary bar. As the sizes of brakes have decreased, however, conventional unitary boring bars have proven unsuccessful in refinishing the smaller sized brakes on many brake lathe machines.
A craftsman seeking to insert a refinishing cutter attached to a conventional boring bar cannot insert the cutter into and against the smaller brakes. The cutter may not fit within the angle formed between the boring bar and the longitudinal axis through the center of the drum and the rotating shaft of a conventional brake lathe adapter or other apparatus holding a rotating brake drum.
Refinishing cutters attached to conventional boring bars cannot be positioned within the decreasing space between (a) a brake mounted on a brake lathe tool or adapter, and (b) the arbor shaft and an adapter that hold a brake during operation and performance of the refinishing work. The amount of travel, or adjustment, between a device designed to hold a boring bar during operation, and the boring bar itself, is limited as regards inboard movement and positioning, and therefore cannot vary to fit into a wide range of brakes.
Use of a variety of variously sized boring bars and refinishing cutters not only is too expensive, it also requires the craftsman performing the refinishing work to change boring bars depending on the size of the brake to be worked on, and therefore adds excessively to the cost of refinishing.
Therefore, a previously unaddressed need exists in the industry for a new, useful and improved apparatus, and method for using such an apparatus, that provides a variable angle refinishing tool and dimensionally variable shaper or cutter head capable of machining, refinishing, balancing, or resurfacing a brake drum regardless of the applicable size or dimensions of the brake drum.
While the apparatus disclosed and claimed in the Pending Application has proven useful for the intended situations and applications described in that document, additional improvements and optimizations shown and claimed in this document provide embodiments in which the different configurations described in this document result in additional and alternative uses for the hubbed rotor adapter plate described and claimed in this document.